Hey, I did not think I would be posting in support section any time soon, but… My friend just bought a 3d printer and asked me to come over and help him with learning modelling in Blender. So… I know Blender is a lot and I was just kind of preparing for that and going through modelling functions and thinking what I could show and tell him in a limited amount of time that would be kind of useful and peak his interest more and I was just testing how it would be to show main/kind of most important modelling operators and so I was playing around with simple geometry and simple modelling operators, you know all the ones in Select, Mesh, Vertex, Edge, Face manus. All well and good right?.. 
I somehow managed to end up with an object:
-nan(ind) m in size apparently. I first noticed that snapping does not work with it and then the dimensions panel… Anyone experienced anything similar?
I was just going through mesh menu and trying things out talking about them in my mind to see what I can manage to tell about them that would be memorable and useful…
I wonder if there is something more about this that I could submit in a bug report. Anyone interested in playing around with it and helping me discover how and why and what might be going on?
5.1 release, I used Add Vertex add-on to create the object:
bl_info = {
"name": "Add Vertex",
"author": "Martynas Žiemys",
"version": (1, 0),
"blender": (2, 80, 0),
"location": "View3D > Add > Mesh > Add Vertex",
"description": "Add Vertex",
"warning": "",
"wiki_url": "",
"category": "Add Vertex",
}
import bpy
from bpy.types import Operator
from bpy_extras.object_utils import AddObjectHelper, object_data_add
from mathutils import Vector
def add_vertex(self, context):
verts = [
Vector((0,0,0)),
]
edges = []
faces = []
mesh = bpy.data.meshes.new(name="Vertex")
mesh.from_pydata(verts, edges, faces)
object_data_add(context, mesh, operator=self)
class OBJECT_OT_add_vertex(Operator, AddObjectHelper):
"""Add Vertex"""
bl_idname = "mesh.add_vertex"
bl_label = "Add Vertex"
bl_options = {'REGISTER', 'UNDO'}
def execute(self, context):
add_vertex(self, context)
bpy.ops.object.mode_set(mode = 'EDIT')
bpy.ops.mesh.select_mode(type='VERT')
bpy.ops.mesh.select_all(action='SELECT')
return {'FINISHED'}
def add_object_button(self, context):
self.layout.operator(
OBJECT_OT_add_vertex.bl_idname,
text="Vertex",
icon='DECORATE')
def register():
bpy.utils.register_class(OBJECT_OT_add_vertex)
bpy.types.VIEW3D_MT_mesh_add.prepend(add_object_button)
def unregister():
bpy.utils.unregister_class(OBJECT_OT_add_vertex)
bpy.types.VIEW3D_MT_mesh_add.remove(add_object_button)
if __name__ == "__main__":
register()
But it’s very innocent and old and well tested… I don’t think it has anything to do with anything. I don’t think I used any other add-ons, just Loop Tools as well, regular every-day normal stuff… But I tried a lot of modelling operators during this. 
Here is the file:
-nan(ind) bug.blend (131.4 KB)
A truly mysterious puzzle. I am just wondering what else besides the file I could add to the bug report…
